Output buffers are widely used in analog circuits to drive large external capacitive loads. One typical application for an output buffer is with a low drop-out (LDO) voltage regulator. The LDO voltage regulator is coupled to a capacitive load through an output buffer. A capacitive load may be a battery. The output buffer load current bandwidth and stability limits the overall LDO voltage regulator settling and power up time. For example, in a LDO voltage regulator, the load current may vary from no load current (0 mA) to about 300 mA. This leads to an approximate 300 times increase in the load current bandwidth, making the output buffer unstable due to high frequency poles.
It will be desirable to have output buffers configured to operate efficiently for various load conditions.